java与es8实战之四：SpringBoot应用中操作es8(无安全检查)
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本篇概览
[*]本篇是《java与es8实战》系列的第四篇，系列文章写到现在，连个HelloWorld都没运行起来，实在说不过去了...
[*]因此，本篇总体目标明确：实战在SpringBoot应用中操作elasticsearch8
[*]为了降低难度，本篇部署的elasticsearch8未设置安全检查，无需证书、账号、密码，只要连接到es的IP和端口就能执行操作
[*]总体目标可以拆解为两个子任务
[*]在SpringBoot中连接elasticsearch8
[*]在SpringBoot中使用elasticsearch8官方的Java API Client
[*]接下来直接开始
部署elasticsearch集群(无安全检查)
[*]关于快速部署elasticsearch集群(无安全检查)，可以参考《docker-compose快速部署elasticsearch-8.x集群+kibana》
Java应用连接elasticsearch的核心套路
[*]不论是直连，还是带安全检查的连接，亦或是与SpringBoot的集成使之更方便易用，都紧紧围绕着一个不变的核心套路，该套路由两部分组成，掌握了它们就能在各种条件下成功连接es
[*]首先，是builder pattern，连接es有关的代码，各种对象都是其builder对象的build方法创建的，建议您提前阅读《java与es8实战之一》一文，看完后，满屏的builder代码可以从丑变成美...
[*]其次，就是java应用能向es发请求的关键：ElasticsearchClient对象，该对象的创建是有套路的，如下图，先创建RestClient，再基于RestClient创建ElasticsearchTransport，最后基于ElasticsearchTransport创建ElasticsearchClient，这是个固定的套路，咱们后面的操作都是基于此的，可能会加一点东西，但不会改变流程和图中的对象
https://img2023.cnblogs.com/blog/485422/202308/485422-20230826091909552-1349723184.png
[*]准备完毕，开始写代码
新建子工程
[*]为了便于管理依赖库版本和源码，《java与es8实战》系列的所有代码都以子工程的形式存放在父工程elasticsearch-tutorials中
[*]《java与es8实战之二：实战前的准备工作》一文说明了创建父工程的详细过程
[*]在父工程elasticsearch-tutorials中新建名为basic-crud的子工程，其pom.xml内容如下
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<parent>
<artifactId>elasticsearch-tutorials</artifactId>
<groupId>com.bolingcavalry</groupId>
<version>1.0-SNAPSHOT</version>
<relativePath>../pom.xml</relativePath>
</parent>
<modelVersion>4.0.0</modelVersion>
<artifactId>basic-crud</artifactId>
<packaging>jar</packaging>
<name>basic-crud</name>
<url>https://github.com/zq2599</url>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-dependencies</artifactId>
<version>${springboot.version}</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-configuration-processor</artifactId>
<optional>true</optional>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
<exclusions>
<exclusion>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>org.junit.jupiter</groupId>
<artifactId>junit-jupiter-api</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.junit.jupiter</groupId>
<artifactId>junit-jupiter-engine</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>co.elastic.clients</groupId>
<artifactId>elasticsearch-java</artifactId>
</dependency>
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
</dependency>
<dependency>
<groupId>jakarta.json</groupId>
<artifactId>jakarta.json-api</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-surefire-plugin</artifactId>
<version>3.0.0-M4</version>
<configuration>
<skipTests>false</skipTests>
</configuration>
</plugin>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
<configuration>
<excludes>
<exclude>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
</exclude>
</excludes>
</configuration>
</plugin>
</plugins>
<resources>
<resource>
<directory>src/main/resources</directory>
<includes>
<include>**/*.*</include>
</includes>
</resource>
</resources>
</build>
</project>编码：配置文件
[*]先准备好配置文件application.yml，内容如下，很简单，只有es的地址信息
elasticsearch:
# 多个IP逗号隔开
hosts: 127.0.0.1:9200编码：配置类
[*]首先把启动类写好，平平无奇的启动类BasicCrudApplication.java
@SpringBootApplication
public class BasicCrudApplication {
public static void main(String[] args) {
SpringApplication.run(BasicCrudApplication.class, args);
}
}
[*]然后是配置类ClientConfig.java，这是本篇的关键，操作ES所需的ElasticsearchClient实例如何创建，ES的IP地址如何传入，全部写在这里了
package com.bolingcavalry.basic.config;
import co.elastic.clients.elasticsearch.ElasticsearchAsyncClient;
import co.elastic.clients.elasticsearch.ElasticsearchClient;
import co.elastic.clients.json.jackson.JacksonJsonpMapper;
import co.elastic.clients.transport.rest_client.RestClientTransport;
import lombok.Setter;
import org.apache.http.HttpHost;
import org.elasticsearch.client.RestClient;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.util.StringUtils;
@ConfigurationProperties(prefix = "elasticsearch") //配置的前缀
@Configuration
public class ClientConfig {
@Setter
private String hosts;
/**
* 解析配置的字符串，转为HttpHost对象数组
* @return
*/
private HttpHost[] toHttpHost() {
if (!StringUtils.hasLength(hosts)) {
throw new RuntimeException("invalid elasticsearch configuration");
}
String[] hostArray = hosts.split(",");
HttpHost[] httpHosts = new HttpHost;
HttpHost httpHost;
for (int i = 0; i < hostArray.length; i++) {
String[] strings = hostArray.split(":");
httpHost = new HttpHost(strings, Integer.parseInt(strings), "http");
httpHosts = httpHost;
}
return httpHosts;
}
@Bean
public ElasticsearchClient elasticsearchClient() {
HttpHost[] httpHosts = toHttpHost();
RestClient restClient = RestClient.builder(httpHosts).build();
RestClientTransport transport = new RestClientTransport(restClient, new JacksonJsonpMapper());
return new ElasticsearchClient(transport);
}
@Bean
public ElasticsearchAsyncClient elasticsearchAsyncClient() {
HttpHost[] httpHosts = toHttpHost();
RestClient restClient = RestClient.builder(httpHosts).build();
RestClientTransport transport = new RestClientTransport(restClient, new JacksonJsonpMapper());
return new ElasticsearchAsyncClient(transport);
}
}
[*]从上面的代码可以看出，配置类已经向Spring容器注册了ElasticsearchClient实例，后面的业务都可以使用此实例来操作ES
编码：服务类
[*]本篇只是为了演示SpringBoot应用如何连接和操作ES，还不会深入ES操作的细节，因此只对索引做一些基本操作即可
[*]先写一个接口IndexService.java，里面定义了多个索引操作的方法
package com.bolingcavalry.basic.service;
import co.elastic.clients.elasticsearch._types.mapping.TypeMapping;
import co.elastic.clients.elasticsearch.indices.IndexSettings;
import co.elastic.clients.util.ObjectBuilder;
import java.io.IOException;
import java.util.function.Function;
public interface IndexService {
/**
* 新建指定名称的索引
* @param name
* @throws IOException
*/
void addIndex(String name) throws IOException;
/**
* 检查指定名称的索引是否存在
* @param name
* @return
* @throws IOException
*/
boolean indexExists(String name) throws IOException;
/**
* 删除指定索引
* @param name
* @throws IOException
*/
void delIndex(String name) throws IOException;
/**
* 创建索引，指定setting和mapping
* @param name 索引名称
* @param settingFn 索引参数
* @param mappingFn 索引结构
* @throws IOException
*/
void create(String name,
Function<IndexSettings.Builder, ObjectBuilder<IndexSettings>> settingFn,
Function<TypeMapping.Builder, ObjectBuilder<TypeMapping>> mappingFn) throws IOException;
}
[*]然后接口的实现，可见所有操作都是在调用ElasticsearchClient实例的API
package com.bolingcavalry.basic.service.impl;
import co.elastic.clients.elasticsearch.ElasticsearchClient;
import co.elastic.clients.elasticsearch._types.mapping.TypeMapping;
import co.elastic.clients.elasticsearch.indices.IndexSettings;
import co.elastic.clients.util.ObjectBuilder;
import com.bolingcavalry.basic.service.IndexService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.ApplicationContext;
import org.springframework.stereotype.Service;
import java.io.IOException;
import java.util.function.Function;
@Service
public class IndexServiceImpl implements IndexService {
@Autowired
private ElasticsearchClient elasticsearchClient;
@Override
public void addIndex(String name) throws IOException {
ApplicationContext applicationContext;
elasticsearchClient.indices().create(c -> c.index(name));
}
@Override
public boolean indexExists(String name) throws IOException {
ApplicationContext a;
return elasticsearchClient.indices().exists(b -> b.index(name)).value();
}
@Override
public void delIndex(String name) throws IOException {
elasticsearchClient.indices().delete(c -> c.index(name));
}
@Override
public void create(String name,
Function<IndexSettings.Builder, ObjectBuilder<IndexSettings>> settingFn,
Function<TypeMapping.Builder, ObjectBuilder<TypeMapping>> mappingFn) throws IOException {
elasticsearchClient
.indices()
.create(c -> c
.index(name)
.settings(settingFn)
.mappings(mappingFn)
);
}
}
[*]以上就是本篇的功能代码了，连接ES在其上进行索引相关操作
编码：单元测试
[*]为了验证上述代码是否生效，接下来写一个单元测试类IndexServiceTest.java，可以重点关注createIndex方法，里面演示了Builder pattern构建参数的详细步骤
package com.bolingcavalry.basic.service;
import co.elastic.clients.elasticsearch._types.mapping.Property;
import co.elastic.clients.elasticsearch._types.mapping.TypeMapping;
import co.elastic.clients.elasticsearch.indices.IndexSettings;
import co.elastic.clients.util.ObjectBuilder;
import org.junit.jupiter.api.Assertions;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import java.util.function.Function;
@SpringBootTest
class IndexServiceTest {
@Autowired
IndexService indexService;
@Test
void addIndex() throws Exception {
String indexName = "test_index";
Assertions.assertFalse(indexService.indexExists(indexName));
indexService.addIndex(indexName);
Assertions.assertTrue(indexService.indexExists(indexName));
indexService.delIndex(indexName);
Assertions.assertFalse(indexService.indexExists(indexName));
}
@Test
void indexExists() throws Exception {
indexService.indexExists("a");
}
@Test
void createIndex() throws Exception {
// 索引名
String indexName = "product002";
// 构建setting时，builder用到的lambda
Function<IndexSettings.Builder, ObjectBuilder<IndexSettings>> settingFn = sBuilder -> sBuilder
.index(iBuilder -> iBuilder
// 三个分片
.numberOfShards("3")
// 一个副本
.numberOfReplicas("1")
);
// 新的索引有三个字段，每个字段都有自己的property，这里依次创建
Property keywordProperty = Property.of(pBuilder -> pBuilder.keyword(kBuilder -> kBuilder.ignoreAbove(256)));
Property textProperty = Property.of(pBuilder -> pBuilder.text(tBuilder -> tBuilder));
Property integerProperty = Property.of(pBuilder -> pBuilder.integer(iBuilder -> iBuilder));
// // 构建mapping时，builder用到的lambda
Function<TypeMapping.Builder, ObjectBuilder<TypeMapping>> mappingFn = mBuilder -> mBuilder
.properties("name", keywordProperty)
.properties("description", textProperty)
.properties("price", integerProperty);
// 创建索引，并且指定了setting和mapping
indexService.create(indexName, settingFn, mappingFn);
}
}
[*]确保不做安全检查的ES集群运行正常，再执行单元测试，如下图，顺利通过，证明所有对ES的操作都符合预期
https://img2023.cnblogs.com/blog/485422/202308/485422-20230826091909485-330078416.png
[*]再用eshead观察product002索引的情况，如下图，三个分片，一个副本，与代码中设置的一致
https://img2023.cnblogs.com/blog/485422/202308/485422-20230826091909604-729631193.png
[*]至此最简单的连接和操作ES实战已经完成，希望本篇能给您一些参考，助您顺利完成基本操作
是不是线程安全的
[*]官方回应：https://discuss.elastic.co/t/is-elasticsearch-client-is-thread-safe/151745
[*]有人在问这个问题，es团队的成员Simon Willnauer的回答是：java的client肯定是线程安全的，golang的不清楚
https://img2023.cnblogs.com/blog/485422/202308/485422-20230826091909514-1605365762.png
[*]对我来说，有他这话就够了，至于golang的嘛，在本文就不讨论了
源码下载
[*]本篇实战的完整源码可在GitHub下载到，地址和链接信息如下表所示(https://github.com/zq2599/blog_demos)
名称链接备注项目主页https://github.com/zq2599/blog_demos该项目在GitHub上的主页git仓库地址(https)https://github.com/zq2599/blog_demos.git该项目源码的仓库地址，https协议git仓库地址(ssh)git@github.com:zq2599/blog_demos.git该项目源码的仓库地址，ssh协议
[*]这个git项目中有多个文件夹，本次实战的源码在elasticsearch-tutorials文件夹下，如下图红框
https://img2023.cnblogs.com/blog/485422/202308/485422-20230826091909520-1490323358.png
[*]elasticsearch-tutorials是个父工程，里面有多个module，本篇实战的module是basic-crud，如下图红框
https://img2023.cnblogs.com/blog/485422/202308/485422-20230826091909487-144731377.png
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